Process for injection of particles in food

ABSTRACT

The present invention relates to a process for injection of refrigerated suspended particles into food products and the products resulting from such process. The present invention applies to the food industry in the field of meat products, and reveals those characteristics which are relevant for the process of preparation of said meat products suspension, to be later aggregated on larger sized meat products, as well as those characteristics which are relevant for said injection process. The main object of the present invention is to increase the final product green weight without incurring loss of flavor, shortening of shelf life, nutritional value or texture, making feasible the incorporation of smaller size pieces to a product featuring a higher commercial value. The term meat products is herein used meaning those products extracted from poultry, fish, cattle, pork, sheep, etc., both with and without fat either in the shape of meat cut or shred, ground meat, frozen meat, semi-frozen meat or refrigerated meat.

The present invention relates to a process for injection of refrigerated suspended particles into food products and the products resulting from such process. The present invention applies to the food industry in the field of meat products, and reveals those characteristics which are relevant for the process of preparation of said meat products suspension, to be later aggregated on larger sized meat products, as well as those characteristics which are relevant for said injection process.

The main object of the present invention is to increase the final product green weight without incurring loss of flavor, shortening of shelf life, nutritional value or texture, making feasible the incorporation of smaller size pieces to a product featuring a higher commercial value.

The term meat products is herein used meaning those products extracted from poultry, fish, cattle, pork, sheep, etc., both with and without fat, either in the shape of meat cut or shred, ground meat, frozen meat, semi-frozen meat or refrigerated meat.

BACKGROUND OF THE INVENTION

The state of the art regarding the present invention can be established with the aid of several documents, among them U.S. Pat. No. 4,960,599 granted to Cozzini et al.

The systems for preparation of the suspension and for its injection in the meat products of the current state of the art may be described based on five main components:

-   -   A) Mixing silo;     -   B) Forced feeding reduction mill;     -   C) Suspension storage silo;     -   D) Return silo, and     -   E) Injection head.

The function of the mixing silo (A) is to store and refrigerate the mix of brine and meat. When it reaches a temperature between −4, 5° C. and −9° C., said mixture is carried to the Forced feeding reduction mill (B), where it is transformed in the suspension (which definition corresponds to a mixture which integrates one or more liquid or oil phases with at least one solid phase). Then said suspension is carried to the Suspension storage silo (C), where a heat exchanger (D) for continuous refrigeration keeps the resulting suspension temperature below. 0° C. After that the suspension is transferred, with the aid of a centrifugal pump (P), to the Injection head (E), equipped with a set of injection needles (F). A conveyor (G) conveys the meat products of commercial dimensions to the Injection head (E). The injection process itself takes place when a commercial dimension meat product, laid under said Injection head (E), is penetrated by its set of injection needles (F). Said needles inject the suspension in multiple points of the meat product. The excess suspension generated on the injection operation is collected on the return silo (H) and sent, with the aid of a lobe pump (not shown) back to the mixing silo (A), closing the cycle.

INCONVENIENCES OF THE STATE OF THE ART

The current state of the art presents some inconveniences.

The Suspension storage silo (C) of the current state of the art systems features a single pump (P), which prevents the use of multiple injectors or injectors with multiple heads, therefore limiting the system's productivity.

Furthermore, the different values of friction and viscosity of the suspension components (meat, brine and optional additives), associated to the mechanical characteristics of the injection process cause the excess suspension collected below the injection head (E) and stored in the return silo (H) not to present the same proportion between the component elements of the suspension. Usually said excess presents a higher meat content than the one originally set by the Forced feeding reduction mill (B) placed between the mixing silo (A) and the Suspension storage silo (C). In the current state of the art systems, the return of the excess suspension from the injector to the mixing silo causes a change in the delicate balance between the suspension components, i.e. a disproportion between the brine and meat products. Said change of suspension balance in turn tends to cause a progressive yield loss in the injection process.

Another inconvenience is that the current state of the art injection systems do not allow a precise and consistent control of the injection pressure. Said injection pressure control is critical for the system's performance. If the injection pressure is too low, the suspension does not penetrate between the fibers of the meat product to be injected, thus keeping the meat product from admitting the suspension quantity originally intended for it. If the injection pressure is too high, the injection damages the meat product (sometimes even turning it to shreds) and also prevents the adequate control of the quantity of suspension aggregated to the meat product.

DESCRIPTION OF THE INVENTION ELEMENTS

The present invention eliminates the inconveniences of the current state of the art by the use of an improved system that incorporates a high performance sequential disc mill for the reduction of the meat products to a dimension which fosters its suspension in a mixture of water, salt and (optional) additives.

The present invention is applied to processes for the injection of suspensions into food products, preferably meat products and fibrous foods in general, as well as poultry and fish.

The present invention will be better characterized with the aid of the annexed drawings, where:

FIG. 1 is an illustrative example of the state of the art systems for the preparation of the suspension and injection in the meat products, wherein the arrows indicate the process flow.

FIG. 2 is a schematic view of the present invention's system, wherein the arrows indicate the process flow.

FIG. 3 details an example of an alternative embodiment for a pneumatic pressure control according to the present invention.

FIG. 4 details the sequential forced feeding disc mill for the reduction of meat products as incorporated to the present invention, seen in a side elevation and also a frontal view.

Based on the figures described above, it is possible to identify in the present invention a refrigerator (1), a mixing silo (2), a forced feeding primary reduction mill (3), a Suspension storage silo (4), a continuous refrigeration system (5), an array of pumps (20), an array of injection heads (6), a set of injection needles (7), a conveyor for transporting the meat products to be injected (8), a return silo (9) and a forced feeding secondary reduction mill (10).

The injection needles set (7) uses different needle types according to the kind of meat product to be injected and the injection conditions.

In an alternative embodiment, the present invention eliminates the need for said injection needles, replacing it by a pressurized suspension pulse, which works in a manner very similar to the corresponding current state of the art medical devices used for vaccine injection in humans.

Forced Reduction Mill

As shown in detail on FIG. 4, the present invention also incorporates a high performance mill that operates coupled to a forced feeding system. The products to be reduced (for example a mixture of brine or only water with meat products) are carried on a forced flux (with the aid of a pump—not shown—which generates pressure upstream of said flux) through a duct (14). Said duct directs the flux in a direction orthogonal to the plan of a reduction or milling unit.

Said reduction unit comprises two or more milling sets, each one of them in turn comprising a rotating blade assembly (15), over which is mounted a certain number of inserts (16), a fixed milling disc (17) and a spacer (18). Said reduction unit incorporates two or more milling sets, successive and in parallel, with the spacing between the successive sets preferably between 15.0 and 60.0 mm.

Each of the rotating blade assemblies (15) presents from 3 to 6 individual blades. Each of the fixed milling plates (17) presents on its surface a set of milling holes with diameters preferably between 0.6 and 5.0 mm. The spacer (18), which function is to create individual chambers to separate the successive reduction sets, is always set after the fixed milling plates (17) in order to bear the force generated by the pressure applied upstream. The pump (19) is set upstream of the last spacer (18), in order to drive the flux out of the mill.

In the process of the present invention, said mill configuration is used both on the forced feeding primary reduction mill (3) and the forced feeding secondary reduction mill

Process Operation

The process operation of the present invention is described below.

Initially the mixing silo (2) is loaded with the ingredients that compose the suspension to be prepared. Said ingredients comprise brine or water, cuts and/or shreds of meat products, optionally including additives such as spices, nitrates, phosphates, binding agents, etc., which act as flavor enhancers and preservatives.

Alternatively, the brine can be processed in an auxiliary silo (not shown) and transferred to the mixing silo (2), passing before through the refrigerator (1).

The mixture is made setting a proportion in weight of at least 60% of brine or water to the total weight of the suspension, with the temperature stabilized between +5° C. and −18° C. once such conditions are achieved, a pump (not shown) drives the mixture to the primary reduction mill (3), where is initiated the reduction milling process using force feeding. Upon passing between the primary reduction mill (3) milling holes, the suspended solids of the mixture are sheared by the array of reduction sets inside the mill. The pump (19) placed right downstream of the last spacer (18), drives the suspension towards the Suspension storage silo (4).

The purpose of transforming the mixture in a suspension is to make it more homogenous, which fosters both the mechanical performance of the injection process and the aspect of the final product.

As explained previously, after passing through the above described reduction unit, the suspension is expelled from the mill with the aid of a pump (19) placed downstream of the last spacer (18). Coming out of the primary reduction mill (3), the suspension is transferred to the Suspension storage silo (4).

Said Suspension storage silo (4) may or may not incorporate a continuous refrigeration system (5). an array of pumps (20) placed downstream of the suspension storage silo (4) drives the suspension stores therein to an array of injection heads (6), where the suspension is injected in the meat products. Said injection is made by injection needles (7) arranged on the array of injection heads (6). In the present invention, said array comprises one or more injection heads or injectors placed along the path of the meat product. The operation of said heads (6) is independent, and each one of the processes meat product pieces passes successively through each one of these heads.

In spite of the pressure adjustment, a minor part of the volume of injected suspension escapes, either through the meat product fibers, the excess retained inside the needles after the injection or even through the very holes created by the penetration of the injection needles. In the alternative embodiment which uses pressurized suspension pulses instead of needles, the volume of excess suspension tends to be smaller.

Said excess suspension is collected by means of a system (not shown) of centralized collection (gravity powered) incorporated to the injector and accumulates in the return silo (9), being later submitted to another cycle of reduction. Said step of reduction of the injection excess is processed in a forced feeding secondary reduction mill (10) placed in the middle of a duct that connects the exit of the return silo (9) and the Suspension storage silo (4), wherein it is reincorporated on the process. This avoids wastage and insures a better suspension refinement. In alternative embodiments of the present invention, which lack the Suspension storage silo (4), the placing of the excess injection recuperation circuit previously described allows the preparation of a new batch of mixture and loading into the Mixing silo (2), because it does not have to receive the injection excess anymore.

zzzInjection Pressure

The injection is made under pressures preferably between 0.5 and 9.0 bar, according to the characteristics of origin, texture, refrigeration state, etc. of the meat product to be processed. In the present invention, the injection pressure control is preferably effected through the variation of the speed of the pumps in the array of pumps (20).

The present invention may present several alternative forms of injection pressure control, according to the operational needs. As alternatives to the variation of the speed of the pumps in the array of pumps (20), the injection pressure control can be effected by two alternative manners. The first alternative for injection pressure control is based on the adjustment of a pressure regulation valve (not shown) placed between the suspension storage silo (4) and the array of injection heads (6), equipped with a return circuit to the suspension storage silo (4). The second alternative for injection pressure control is based in the use of a pneumatic device as illustrated in FIG. 3. Said pneumatic device provides injection pressure control in the following manner: An enclosed tank (12), alternatively placed between the Suspension storage silo (4) and the injection heads (6), or even (alternatively) a small reservoir placed inside the injector itself, stores the suspension and also a certain volume of air. A pressure regulation valve (11) controls the pressure of the air contained inside the enclosed tank (12). Sharing the same manifold, the air and the suspension volume contained by the enclosed tank (12) consistently present the same pressure values. The injection needles set (13) is directly connected to the bottom of the enclosed tank (12) by means of a duct.

The present invention offers multiple advantages compared to the current state of the art.

The placement of two or more distribution pumps in the array of pumps (20) in the Suspension storage silo (4) allows the use of several injectors or multiple headed injectors, therefore fostering the system's performance.

The excess suspension collection system of the present invention fosters the processing efficiency, avoiding wastage.

The additional reduction step of said excess injection ensures the consistency of the proportion between the suspension component elements, warranting a constant balancing of the suspension provided to the array of injection heads (6), enhancing the performance of the injection process.

Another advantage of the present invention lies in the degree of precision and consistency of the injection pressure control, critical for the system performance. The injection pressure control which characterizes the present invention ensures that the quantity of suspension added to the meat product is exactly the one originally planed, preserving the integrity of the processed meat product.

Finally, another advantage of the present invention is the high processing speed afforded by the use of forced reduction milling, which accelerates the conversion of the mixture into a suspension.

Those skilled in the art will promptly realize that the description of one of the preferential embodiments previously given does not limit the application of the present invention to processes featuring those characteristics described herein, so that it can be applied to other similar processes without abandoning the scope and inventive spirit covered by the following set of claims. 

1. A process for injection of refrigerated suspended particles in food products comprising a refrigerator (1), a mixing silo (2), a forced feeding primary reduction mill (3), a suspension storage silo (4), a continuous refrigeration system (5), an array of injection heads (6), an injection needle set (7), a conveyor (8) for transporting the product to be injected and a return silo (9), characterized by the fact that it additionally features a second forced feeding reduction mill (10).
 2. A process according to claim 1, incorporating at least two of said forced feeding reduction mills, characterized by the fact that the flow of products to be reduced is driven to said mill through a forced duct with a pressure generating device placed in a point upstream of the mill intake.
 3. A process according to a claim 1 or 2, incorporating at least two of said forced feeding reduction mills, characterized by the fact that said mill preferably presents more than one reduction or milling unit, successive and in parallel, with each one of said units preferably incorporating one rotating blade assembly (15), over which is mounted a certain number of inserts (16), one fixed milling plate (17) and one spacer (18), with a pump (19) placed downstream of said last spacer (18).
 4. A process according to claims 1, 2 or 3, incorporating at least two of said forced feeding reduction mill, characterized by the fact that the spacing between said successive reduction or milling sets is between 15.0 and 60.0 mm, with each one of the fixed milling plate (17) presenting on its surface a set of milling holes with diameters preferably between 0.6 and 5.0 mm.
 5. A process according to claims 1, 2, 3 or 4, incorporating additionally a device for collecting excess suspension connected to a return silo (9) placed upstream of the array of injection heads (6), characterized by the fact that the excess suspension collected after the injection process is processed by a second reduction device before it is once again introduced in the processing flow.
 6. A process for injection of refrigerated particles suspension in food products comprising a refrigerator (1), a mixing silo (2), a forced feeding primary reduction mill (3), a suspension storage silo (4), a continuous refrigeration system (5), an array of injection head (6), an injection needles set (7), a conveyor (8) for transporting the product to be injected and a return silo (9), characterized by the fact that it features, in an alternative embodiment, an array of pumps (20) incorporating two or more pumps, placed upstream of the suspension storage silo (4), being said array of pumps (20) coupled to distribution conducts that lead to multiple refrigerated suspension injector devices, or else to injector devices equipped with multiple injection heads.
 7. A process according to claims 1, 3, 4, 5 or 6, characterized by the fact that it features a device for injection pressure control through the control of the speed of the pumps in the array of pumps (20).
 8. A process according to claims 1, 3, 4, 5, 6 or 7, characterized by the fact that it alternatively features a device for injection pressure control through the adjustment of a pressure regulation valve (11) placed upstream of an enclosed tank (12).
 9. A process according to claims 1, 3, 4, 5, 6, 7 or 8, characterized by the fact that it alternatively features a device for injection pressure control through the adjustment of a pressure regulation valve placed between the suspension storage silo (4) and the array of injection heads (6), equipped with a return circuit directed to the suspension storage silo (4).
 10. A process according to claims 1, 3, 4, 5, 6, 7, 8 or 9, characterized by the fact that it eliminates the need of an injection needles set (7), replacing it by a pressurized suspension pulse.
 11. A process according to claims 1, 3, 4, 5, 6, 7, 8 or 9, characterized by the fact that it uses different types of needles depending on the type of meat product to be injected and the injection conditions.
 12. A process according to claims 1, 3, 4, 5, 6, 7, 8, 9, 10 or 11, characterized by the fact it alternatively uses an auxiliary silo for the processing of mixture components before they are transferred to the mixing silo (2), passing before through a refrigerator (1).
 13. products characterized by the fact that they are obtained through the process described in claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or
 12. 